Analysis of the ignition delay effects on monopropellant self-excited pulse thruster

The ignition delay is an important factor which needs to be considered carefully in the pulse thruster design. To investigate the effects of ignition delay on the self-excited pulse thruster, a mathematical model was set up to describe the pulsating process adopting HAN (Hydroxylammonium Nitrate)-based monopropellant. The impact on the pressure, mass flow, thrust and specific impulse of the thruster was analyzed when the ignition delay was changed. For the self-excited thruster, the ignition delay strengthens the extrusion, injection and combustion process. With the delay increasing, the duration of the combustion in a cycle and the whole cycle period become much shorter, and the magnitude of the pressure peak both in the extrusion room and in the combustion chamber ascend obviously at the same time. Few influence of the delay on the average specific impulse in a cycle period is observed though the longer delay would result in the higher average thrust. The ignition delay may be a possible approach to adjust the pulsating characteristics of the self-excited pulse thruster. Thus, the relative study is important to explore and apply this novel rocket engine.